What if your fave social network started ranking you by how different you are from your friends?
What if your website was suddenly mostly Icelandic?
What if your music site thought you should listen to country music?

Explain: “game designers take fun seriously” people feel pleasure when completing a series of steps – add variables like timing and amount of rewards to spur behaviour

3) All your friends are there

Explain: desire for connections and “a place to hang out” … (in these games) “who you know is more important than what you know” & “status is everything” (which requires significant time investment) … each new player validates existence of this place